65- 
Potamogeton natans L., Myriophyllum Farwellii Morong., 
Ranunculus aquatilis L • var. oapillaoeue PC •, Hippuris 
vu lgari s L. 
The commonest large aquatic is Nymphaea 
advena Ait. (yellow pond lily); it sometimes forms patches 
extending half way across the stream. Castalia tuberosa 
(Paine) Creene (white pond lily) is much less common, 
though it occasionally occurs in large patches; the same 
may he said of the water-shield ( Brasenia Schg&beri Gmel.). 
In many places the stream is fringed with overhanging shrubs 
as shown in fig. 44. Mud banks often occur at the bends, 
supporting various aquatic or amphibious species, such as 
Potentilla palustris (L.) Scop, (marsh cinque-foil), 
Sparganium ey ryoarpum Engelm. (bur-reed)., Bleocharis 
aoicularis (L.) R. & S. t Carex filiformis Good, (bog sedge) 
and Car ex striota Lam. The last two species form clumps 
at various points along the bank, thus enabling other species 
to obtain a footing. 
The shrubby growth along the banks 
consists principally of the following:- ALmus incana (L.) 
Moench. (hoary alder). Hex verticillata (L.) A. Gray (win¬ 
ter-berry), Cornus stolonifera Miohx. (red-osior dogwood), 
Chamaedaphne calyculata (L.) Moench. (leather-leaf). 
Spiraea salioifolia Roi (meadow-sweet), Salix petiolaris 
